1. Field of the Invention
One or more embodiments of the invention are based in the field of medical engineering and relates to an implantable electrode lead, and an electrode lead assembly. One or more embodiments of the invention furthermore relates to an implantable hydrogel sensor and its use. Furthermore, at least one embodiment of the invention relates to a method to determine the temperature of the electrode of an electrode lead, and a method for operating a nuclear magnetic resonance tomograph, and its use.
2. Description of the Related Art
Electrode leads of the type in question are known in various embodiments and are used routinely e.g. in the field of electrophysiology to detect and treat conduction defects in the heart or the nervous system. Depending on the application, they are also referred to e.g. as a stimulation electrode, a cardiac pacemaker electrode, an ICD electrode (ICD=implantable cardioverter) or an electrophysiology catheter. They have been described numerous times in patent literature. Reference is made in this context, merely for the purpose of providing examples, to the publications DE 10 2005 039 040 A1, DE 198 00 697 A1, DE 20 2006 020 517 U1, and EP 0 306 442.
As is known per se to a person skilled in the art, electrode leads that are present in a patient's body can cause problems during an examination using a nuclear resonance tomograph. In nuclear resonance tomography or magnetic resonance tomography (MRT=magnetic resonance tomography), atomic nuclei are forced by strong magnetostatic fields to precess about the field direction, and they undergo resonant excitation by high frequency electromagnetic alternating fields. When the alternating fields are shut off, the atomic nuclei return to their original direction; the relaxation times are characteristic for various types of tissue, thereby making exact imaging possible.
However, when a patient has an implanted electrode lead, there is a risk that its electrodes and the surrounding tissue layers will heat up. This is caused by electrical induction currents that are generated by the strong electromagnetic alternating fields of the nuclear resonance tomograph. For this reason, the diagnostic utility of an examination based on nuclear resonance tomography must be weighed carefully against the risk of disadvantageous side effects. This situation is made more difficult by the fact that the heating of the electrodes depends on the particular scan parameters of the examination and, in particular, on the positioning of the electrode lead in the electromagnetic alternating field, thereby often rendering it impossible to make reliable prognoses in clinical practice. As a result, patients who have an implanted electrode lead are typically denied an examination using nuclear resonance tomography, which is harmless per se.
The object of the at least one embodiment of the invention, therefore, is to provide an implantable electrode lead for the medical application, using which an examination based on nuclear resonance tomography can be performed in a safe, reliable manner. In addition, an electrode lead of this type should be easy to use and cost effective to manufacture in high-volume production. These and further objects are solved according to the proposed invention by an electrode lead and an electrode lead assembly having the features as described and claimed herein. Advantageous embodiments of embodiments of the invention are also described and claimed herein.